[TUHS] running BSD 2.11 on my PDP 11/70 emulator

[Kenneth Goodwin]

Something is definitely off with memory layout.
That 300000 user memory is not a reference to even the maximum  split i/d
image size.

If your bsd image has kernel dynamic buffer configuration limit
parameters,  you could tweak those down say 50% to see what happens.  (Not
a BSD kernel hacker and it's been a while since I last read over the source
code)



On Mon, Apr 7, 2025, 8:02 AM Kenneth Goodwin <kennethgoodwin56 at gmail.com>
wrote:

> To me it looks like a memory issue of some sort. Setup of the MMU etc.
>
> 1. Your user memory is less than 10% of "available memory" which should be
> the amount left after the kernel loads and allocates dynamic  buffers. User
> memory should be alot closer to available number. Unless it is referring to
> limits of mmu per process and not total available for all user level
> programs.
>
> 2. The bulk of the text dump seems to just be random initialized data
> dumped from Ram.
> Aka - Printf() format strings.  Indicates that the wrong address in memory
> is potentially being accessed.
>
> Perhaps the pdp11 emulator configuration does not have a correct mmu for
> your image file.
>
> For example,  you are running the 11/70 emulation and the binary image you
> are running is actually compiled for a pdp 11/45.
>
> The 11/70 has an mmu supporting split instruction and data spaces. 64k
> instruction,  64k data. But the kernel you are using was compiled to run on
> a non split I And D version of the pdp11 supporting only 64kb of combined
> user and data.
>
> On Mon, Apr 7, 2025, 3:30 AM Folkert van Heusden <folkert at vanheusden.com>
> wrote:
>
>> Hi,
>>
>> For fun I'm developing a PDP 11/70 emulator. It runs on everything from
>> ESP32 microcontrollers up to linux, windows, etc
>> https://vanheusden.com/emulation/PDP-11/kek/
>> Currently it can run UNIX 7 in multi user mode.
>> Of course I would like it to run BSD 2.11 as well (because of the
>> networking support). It boots, but after outputting the memory amounts
>> it produces a lot of garbage. It does eventually complete booting and
>> then allows you to log in.
>> I wonder if you sees this:
>> https://paste.nurd.space/mqIDB_0SjoDoJoasOGkiNQ_NjpRsCufAJCnKTA7ZxUI
>> (text) or
>>
>> https://imgpaste.nurd.space/pics/437bcf0d149a017168cbbf2def8560917a037a3935c5c3aa1fbea2f7e43b485a.png
>> (image), does this ring a bell to anyone? I verified with simh that the
>> disk-image should work.
>>
>>
>> regards
>>
>> --
>> www.vanheusden.com
>>
>
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